Hi,nI will try what you say. Thanks for your patience and help.nI read this in ansys maxwell help;nTypical boundary conditionsused in eddy current problems include magnetic field tangent(the default, natural boundary condition which is automatically applied on all surfaces of the problem space -the surfaces of the geometry entity containing the model inside it). This default boundary condition can be overwritten if other boundary conditions are applied on exterior surfaces of the solution space. The default boundary condition confines the magnetic field to the solution space and thus this boundary must be placed at some distance from the sources of the problem to avoid over-constraining the fields by placing the boundaries to close to the model objects. While it is dif­ficult to provide recipes with general validity on the placement of the boundaries of problems, a good rule of thumb says that if a model can be imagined as being contained in a sphere of radius R, the boundaries can be placed at a 4-5 radii R from the imaginary center of the model.nAccording to this explanation, is the radius definition that I will create for the region that I show in the picture below?nnn